JP4164421B2 - Oscillating device, optical deflector using the oscillating device, image display device using the optical deflector, image forming apparatus, and manufacturing method thereof - Google Patents

Description

  The present invention relates to an oscillating device, an optical deflector using the oscillating device, an image display device using the optical deflector, an image forming apparatus, and a manufacturing method thereof.

  In recent years, attempts have been made to produce electromagnetic actuators on a substrate such as silicon using a semiconductor process. When an electromagnetic actuator is manufactured using a semiconductor process, a stator, a mover, and an electromagnetic coil can be manufactured in a lump, and there is no need for a bonding or bonding process. The stator, the mover, and the electromagnetic coil can be made with high accuracy. Alignment is possible. In addition, it can be manufactured in large quantities at a time, so cost reduction can be expected.

  One application example of an electromagnetic actuator fabricated on a substrate is an optical deflector. The optical deflector is used in an image forming apparatus such as a laser beam printer, an image display apparatus such as a head mounted display, and an image input apparatus such as a barcode reader. Some optical deflectors can deflect two axes.

  FIG. 10 shows an example of an electromagnetic actuator manufactured on a substrate that can be deflected biaxially by applying it to an optical deflector (see Patent Document 1). FIG. 10 is a top view showing an optical deflector described as one example in Patent Document 1. In FIG. This is a torsion beam light deflector and is used as a deflector for two-dimensionally scanning laser light. This torsion beam optical deflector includes an inner y-axis direction deflecting unit 1003 and an outer x-axis direction deflecting unit 1004. An inner y-axis direction deflecting unit 1003 includes a substrate 1001 having a groove 1002, a movable plate 1006 supported by a shaft 1005 so as to be swingable, and a thin film showing hard magnetism formed on the surface, and a movable plate 1006. A pair of thin film electromagnet portions 1007 to be swung and a mirror 1008 provided on a movable plate 1006 are included. The formation surfaces of the movable plate 1006 and the thin film electromagnet portion 1007 are slightly shifted in the thickness direction. Coulomb generated between a magnetic field generated by passing an alternating current of 60 kHz, which is a structural resonance frequency of the y-axis direction deflecting unit 1003, to the thin film electromagnet unit 1007 and a magnetic field generated in the hard magnetic thin film formed on the movable plate 1006. The movable plate 1006 is swung by force, and the irradiated light is deflected by the mirror 1008. Low power consumption can be realized because of the driving method using mechanical resonance. The outer x-axis direction deflecting unit 1004 has the same structure as the y-axis direction deflecting unit 1003, and the driving method is also the same. The drive frequency of this optical deflector is 60 kHz (y axis), 60 Hz (x axis), and the deformation angle of the movable plate 1006 is ± 13.67 ° (y direction).

  In addition, there is an attempt to reduce the size of an electromagnetic actuator using a semiconductor process and a permanent magnet, and apply this to an optical deflector. A magnetic field can be formed relatively easily by using a permanent magnet, and high speed operation can be expected by reducing the weight of the mover. One example is shown in FIG. 11 (see Patent Document 2). FIG. 11 is a top view showing an optical deflector described as one example in Patent Document 2. FIG. In this optical deflector, a flat movable plate having a mirror is supported by two torsion springs so as to be swingable with respect to the substrate. In FIG. 11, 801 is a galvanometer mirror, 802 is a silicon substrate, 803 is an upper glass, 804 is a lower glass, 805 is a movable plate, 806 is a torsion spring, 807 is a planar coil, 808 is a total reflection mirror, 809 is a contact pad , 810A, 810B, 811A, and 810C represent permanent magnets, respectively. The movable plate 805 is provided with a driving planar coil 807 that generates a magnetic field when energized at the periphery, and applies a static magnetic field only to both side portions of the driving planar coil parallel to the axial direction of the torsion spring 806. The permanent magnets 810A, 810B; 811A, 810C paired with each other are installed on the upper and lower surfaces of the semiconductor substrate via the upper and lower glass substrates 803, 804 so as to give. In this optical deflector, a Lorentz force is applied in a direction in accordance with Fleming's left-hand rule by energizing the driving planar coil 807 and the current flowing through the planar coil 807 and the direction of magnetic flux density by the permanent magnets 810A, 810B; 811A, 810C. F (not shown) works to generate a moment for swinging the movable plate 805. When the movable plate 805 swings, a spring reaction force F ′ (not shown) is generated due to the rigidity of the torsion spring 806. If the current flowing through the planar coil 807 is continuously repeated as an alternating current, the movable plate 805 having the light reflecting surface is oscillated, thereby scanning the reflected light. This patent document 2 discloses another embodiment in which a galvano mirror 801 is installed in place of the total reflection mirror 808 to have a nested structure and enable biaxial scanning.

In addition, although not an electromagnetic actuator, there is an attempt to scan in a biaxial direction with a simple configuration using a movable plate having a nested structure. Here, by making the shape of the movable plate having the deflecting portion a parallelogram, scanning in the biaxial direction is enabled by the driving means in the uniaxial rotational direction. One example is shown in FIG. 12 (see Patent Document 3). FIG. 12 is a top view showing one of the embodiments disclosed in Patent Document 3. As shown in FIG. In FIG. 12, 901 is an optical deflector, 902 is a first torsion spring, 903 is a second torsion spring, 904 is a first movable plate, 905 is a second movable plate, 906 is a support substrate, 907a and 907b are electrodes, 908 Indicates a fixed part. The first movable plate 904 is supported on the support substrate 906 via the fixed portion 908 and the first torsion spring 902. The first movable plate 904 supports the second movable plate 905 via a second torsion spring 903 that is orthogonal to the first torsion spring 902. The shape of the second movable plate 905 is a parallelogram. The center of gravity G of the second movable plate 905 is located at the intersection of the first rotation axis A and the second rotation axis B. The support substrate 906 is provided with two electrodes 907a and 907b, and a voltage can be selectively applied between these electrodes and the back surface of the first movable plate 904. A deflecting unit such as a mirror is installed on the second movable plate 905 to function as an optical deflector. In a state where no voltage is applied, the first movable plate 904 and the second movable plate 905 are positioned at the neutral position. When a voltage is alternately applied to the electrodes 907a and 907b, an electrostatic force acts alternately on the left and right end portions of the first movable plate 904, and swings about the first rotation axis A. At the same time, the second movable plate 905 swings due to a rotational moment acting around the second rotation axis B due to the mass asymmetry.
JP 2000-235152 A Japanese Unexamined Patent Publication No. 7-15005 JP 2001-75042 A

However, each of the optical deflectors described above has the following problems.
The optical deflector disclosed in Patent Document 1 shown in FIG. 10 achieves high-speed operation around two axes. However, since the core constituting the thin-film electromagnet portion 1007 is a thin film formed by sputtering, There is a limit to increasing the area. Therefore, it is inevitable that the magnetic flux is saturated when a large current is passed through the thin film electromagnet portion 1007, and it is difficult to further increase the deformation angle. Further, there is a slight shift in the thickness direction of the formation surface of the movable plate 1006 and the thin film electromagnet portion 1007, and it is difficult to further increase the deformation angle from this point.

  In the optical deflector disclosed in Japanese Patent Application Laid-Open No. 7-15005 shown in FIG. 11, the distance between the upper and lower glass substrates 803 and 804 and the movable plate 805 is increased by increasing the deflection angle of the light when scanning the light. Must. For this reason, the relative distance between the permanent magnets 810A, 810B; 811A, 810C and the driving planar coil 807 increases, and as a result, the magnetic flux density in the planar coil 807 decreases, and a large current is required for driving. .

  In the optical deflector disclosed in Japanese Patent Laid-Open No. 2001-75042 shown in FIG. 12, since the second movable plate 905 having the deflecting portion has a parallelogram shape, the light having a circular beam spot such as a laser beam. When this deflection is attempted, it is necessary to make the second movable plate 905 larger than the area where the light hits. As the second movable plate 905 becomes larger, it is difficult to expect further speeding up and downsizing.

  The object of the present invention is to solve the problems in the above-mentioned conventional ones, to enable high-speed operation with large displacement, high energy efficiency, low cost, and a swing device capable of swinging on two axes. An optical deflector using the apparatus, an image display device using the optical deflector, an image forming apparatus, and a manufacturing method thereof.

  The oscillating device of the present invention that solves the above problems includes a first movable plate that oscillates about a first rotation shaft, and a first elastic support portion that supports the first movable plate so as to be able to oscillate. , A support substrate for fixing the first elastic support portion, a first magnetic field generating means disposed at a position spaced from the first movable plate, and a second movable swinging about the second rotation axis A swinging device comprising a plate and a second elastic support part that supports the second movable plate in a swingable manner and is fixed to the first movable plate. The coil is provided so as to go around the second movable plate, and the second movable plate is provided with second magnetic field generating means. As in this configuration, the two movable plates are nested, and the magnetic field generating means is arranged on the inner second movable plate, the coil is arranged on the outer first movable plate, and the first movable plate is separated from the first movable plate. By installing each magnetic field generating means, it is possible to swing about two axes with a single coil, and because of a very simple configuration, downsizing can be expected and it can be inexpensive. Further, the operation of the movable plate can be controlled by changing the current flowing through the coil. Further, since the coil circulates around the second movable plate, the magnetic flux is effectively applied to the magnetic field generating means on the second movable plate, and the energy efficiency is improved. Furthermore, since the support substrate and the magnetic field generating means can be easily arranged with respect to the movable plate in a positional relationship that does not hinder the swinging movement of the movable plate, the displacement of the movable body can be increased.

Based on the above basic configuration, the following modes are possible.
The first magnetic field generating means may be installed on the support substrate. Thus, the first magnetic field generating means is installed on the support substrate, so that the entire device can be reduced in size.

  The first coil can circulate around the second movable plate in a square shape. By rotating the coil in a square shape in this way, it is easy to obtain a generated force in the direction of swinging the movable plate around the rotation axis, and energy efficiency is improved.

  The direction of the magnetic field of the second magnetic field generating means and the direction of the second rotation axis can be made orthogonal to each other. Further, the direction of the magnetic field of the first magnetic field generating means and the direction of the first rotation axis may be orthogonal to each other. As in these configurations, by devising the positional relationship between the magnetic poles of the magnetic field generating means and the rotating shaft of the movable plate, it is possible to effectively obtain the generated force in the direction of swinging the movable plate around the rotating shaft. And energy efficiency is improved.

  The first coil has at least one of a conductive wire extending in a direction substantially perpendicular to the magnetic field direction of the first magnetic field generation means and a conductive wire extending in a direction substantially perpendicular to the magnetic field direction of the second magnetic field generation means. I can do it. As in this configuration, by devising the positional relationship between the magnetic poles of the magnetic field generating means and the coil conductors, it is possible to effectively obtain the generated force in the direction of swinging the movable plate about the rotation axis. Efficiency is improved. A typical example is the rectangular coil.

  A second coil is further installed on the first movable plate, the first movable plate has a first opening in the inner peripheral portion of the second coil, and the N pole of the first magnetic field generating means The S pole can be arranged so as to sandwich the first opening at a position separated from the first movable plate in a direction substantially perpendicular to the first movable plate. By disposing the magnetic poles of the magnetic field generating means as in this configuration, the distance between the magnetic poles and the movable plate can be easily determined, and the structure can be optimized according to the desired displacement of the movable plate. Further, the operation of the movable plate can be controlled by using a coil as the driving means and changing the current flowing therethrough. Further, since the movable plate has an opening, there is no interference between the magnetic field generating means and the movable plate, and the movable plate can be displaced greatly.

  The second coil and the third coil are further installed on the first movable plate with the first rotation shaft interposed therebetween, and the first movable plate is further disposed on the inner peripheral portion of the third coil. And the N pole and S pole of the third magnetic field generating means sandwich the second opening at a position spaced from the first movable plate in a direction substantially perpendicular to the first movable plate. It can also be arranged. Like this configuration, on the first movable plate, by installing a plurality of coils across the first rotation shaft, the generated force can be increased compared to the configuration having the second coil, Large displacement of the movable plate.

  At least two of the first coil, the second coil, and the third coil may be electrically connected in series. Thus, by connecting two or more coils in series electrically, two or more coils can be driven by one current source. That is, the movable plate can be driven in two axes with one current source, and the configuration is very simple.

  As the magnet, a permanent magnet or an electromagnet can be used. However, since the permanent magnet has no Joule heat loss, energy efficiency is improved. Further, by using a permanent magnet, the configuration can be simplified and the size can be reduced.

Appropriately applying a current containing one or both of the torsional resonance frequency of the first movable plate and the torsional resonance frequency of the second movable plate to the first, second, and third coils, respectively, It is possible to increase the displacement angle of one or both of the first movable plate and the second movable plate by causing a torsional resonance motion in the movable plate.

  At least two of the first movable plate, the first elastic support portion, the second movable plate, the second elastic support portion, and the support substrate may be formed of the same member. As in this configuration, for example, by forming the movable plate, the elastic support portion, and the support substrate from the same member, the assembly process can be eliminated, and the cost can be reduced. In addition, alignment between the movable plate and the support substrate becomes unnecessary, and variation between lots is reduced.

  At least one of the first movable plate, the first elastic support portion, the second movable plate, the second elastic support portion, and the support substrate can be made of single crystal silicon. As in this configuration, for example, by using single crystal silicon for the movable plate and the elastic support portion, the attenuation coefficient of the elastic support portion is reduced, so that a large Q value can be obtained when driven at the resonance frequency. . In addition, since fatigue failure due to repeated deformation does not occur like a metal material, a long-life optical deflector or the like can be configured.

  At least one of the first coil, the second coil, and the third coil may be a planar coil. Any type of coil may be used, but if a planar coil or a coil in which this is laminated is used, the movable plate can be reduced in weight and size.

  Further, the optical deflector of the present invention that solves the above-mentioned problems is an optical deflector using the oscillating device, wherein the second movable plate is provided with a deflecting portion for deflecting incident light. It is characterized by. With this configuration, it is possible to provide an optical deflector that can be deflected to two axes that are very small and inexpensive. The deflecting unit includes, for example, a mirror, a lens, or a diffraction grating. In the case where the deflection unit is configured by a mirror, an optical deflector that is easy to manufacture and has a small mass of the movable part can be provided. When the deflecting unit is constituted by a lens, a transmission type optical deflector having a large deflection angle can be provided, and a light deflection range can be brought on the opposite side of the optical deflector with respect to the light incident direction. The degree of freedom in design arrangement of each part increases. Further, when the deflecting unit is constituted by a diffraction grating, incident light can be deflected as a plurality of beams.

  An image display device of the present invention that solves the above problems includes a light source, the optical deflector that deflects light emitted from the light source, and an image display surface on which the light deflected by the optical deflector is projected. It is characterized by having. Light is projected through optical elements such as lenses, mirrors, and diffraction gratings. By applying the above optical deflector to the image display device as in this configuration, a very small and inexpensive image display device can be provided.

  An image forming apparatus of the present invention that solves the above problems includes a light source, the above-described optical deflector that deflects light emitted from the light source, and a photosensitive material onto which the light deflected by the optical deflector is projected. It is characterized by having. Light is projected through optical elements such as lenses, mirrors, and diffraction gratings. By applying the above optical deflector to the image forming apparatus as in this configuration, a very small and inexpensive image display apparatus can be provided.

  Further, in the method of manufacturing the oscillation device or the optical deflector according to the present invention for solving the above-described problems, a step of forming the movable plate, the elastic support portion, and the support substrate from the substrate, and a coil is formed on the first movable plate. The method includes at least a step, a step of forming a second magnetic field generating unit on the second movable plate, and a step of forming the first magnetic field generating unit on the support substrate. Furthermore, you may have the process of forming a deflection | deviation part in a movable plate. As a result, it is possible to manufacture an oscillating device such as an optical deflector that can be deflected biaxially with a simple structure. In addition, the movable plate and the elastic support portion can be manufactured at a time. Further, alignment between the movable plate and the support substrate is unnecessary, an assembling process is unnecessary, and the cost can be reduced.

  In the manufacturing method, the step of forming the movable plate, the elastic support portion, and the support substrate using the substrate can include reactive ion etching or etching using an alkaline solution. By performing reactive ion etching as in the former, the shape of the movable plate and the elastic support portion can be formed with high accuracy and stability. Like the latter, by performing anisotropic etching due to the etching rate difference of the silicon crystal surface using an alkaline solution, the shape of the movable plate and the elastic support portion can be formed accurately and stably, Since the etching rate is faster than reactive ion etching, the time can be shortened, leading to cost reduction.

  Further, at least one of the step of forming the second magnetic field generating means on the second movable plate and the step of forming the first magnetic field generating means on the support substrate may be performed by plating. Thus, by producing the magnetic field generating means by plating, an assembling process is unnecessary and the cost is low. Further, alignment between the movable plate and the support substrate is unnecessary, and variation between lots is reduced. Furthermore, compared with vapor deposition or sputtering, the magnetic field generating means can be formed at a high speed.

  According to the oscillating device such as the optical deflector of the present invention, it is easy to realize a large stroke as compared with the conventional optical deflector. In addition, a structure with little leakage of magnetic flux can be realized, and energy efficiency is good. Also, by using a plurality of electromagnetic coils, it is possible to realize a swinging device such as an optical deflector that can generate a large force, have a large displacement angle or deflection angle, can operate at high speed, and has a long life and high energy efficiency. Further, according to the image display device and the image forming apparatus of the present invention, it is possible to provide a very small and inexpensive image display device and image forming apparatus.

Hereinafter, examples will be described with reference to the drawings to clarify the embodiments of the present invention.
[Example 1]
A first embodiment of the present invention will be described with reference to FIGS. First, the structure will be described. 1 and 2 show the configuration of the optical deflector of the present embodiment, FIG. 1 (a) is a top view, FIG. 1 (b) is a cross-sectional view along AA ′ in FIG. 1 (a), 2A is a cross-sectional view taken along line BB ′ in FIG. 1A, and FIG. 2B is a bottom view. 1 and 2, reference numeral 101 denotes an optical deflector, and the dimensions are as shown in FIG. The support substrate 106 supports the first movable plate 104 through the first torsion spring 102 so as to be swingable. Further, the first movable plate 104 supports the second movable plate 105 in a swingable manner via a second torsion spring 103 that is orthogonal to the first torsion spring 102. The size of the second movable plate 105 is 1 mm □. The support substrate 106, the first torsion spring 102, the second torsion spring 103, the first movable plate 104, and the second movable plate 105 are integrally formed by a semiconductor process. In the drawing, two first and second torsion springs are provided. Each of the pair of torsion springs is disposed on the same axis. Each pair of torsion springs is disposed on both sides of the movable plate to which the pair is connected. Each movable plate can tilt or reciprocate around the axis of a torsion spring connected thereto.

  A feature of this embodiment is that the first movable plate 104 has a coil 107 and the second movable plate 105 has a deflection unit 108. The coil 107 is made of a low-resistance metal such as copper or aluminum, and the first movable plate 104, the first torsion spring 102, and the support substrate 106 are electrically insulated. The deflecting unit 108 is composed of optical elements such as a mirror, a lens, and a diffraction grating. Further, as shown in FIG. 2B, the first permanent magnets 109a and 109b are installed on the back surface of the support substrate 106, and the second permanent magnet 110 is installed on the back surface of the second movable plate 105, respectively. The magnetic poles of the first permanent magnets 109a and 109b may be as long as the N pole and the S pole are opposed to each other, and may not be as shown in FIG. For example, even if one U-shaped permanent magnet is installed instead of the first permanent magnets 109a and 109b, the N pole and the S pole can be made to face each other. The magnetic poles of the second permanent magnet 110 are as shown in FIG. 2B, but the N pole and the S pole may be interchanged. The first permanent magnets 109a and 109b and the second permanent magnet 110 are made of a material magnetized with a hard magnetic material such as samarium cobalt or neodymium iron boron. The first permanent magnets 109a and 109b and the second permanent magnet 110 may include a magnetic yoke made of a ferromagnetic material such as iron, nickel, cobalt, or an alloy thereof. A current source 111 is electrically connected to the coil 107 in series. Here, the first permanent magnets 109a and 109b and the second permanent magnet 110 are installed on the back surface of the support substrate 106, and the deflection unit 108 is installed on the front surface of the support substrate 106, but they may be on the front surface or the back surface.

Next, the operation will be described.
First, the operation of the second movable plate 105 that swings around the y-axis, that is, the second torsion spring 103 will be described. When a current is passed from the current source 111 to the coil 107 in the direction of the arrow, a magnetic pole (upper surface is N pole and lower surface is S pole) corresponding to the current flowing through the coil 107 is generated on the upper and lower surfaces of the coil 107. The generated magnetic field H is proportional to the product of the current I flowing through the coil 107 and the number N of turns of the coil 107. The magnetic field H acts on the magnetic pole of the second permanent magnet 110, and the second movable plate 105 swings around the second torsion spring 103. The generated torque T is expressed as the product of the magnetization m of the second permanent magnet 110 and the magnetic field H. Therefore, it can be seen that the generated torque T is proportional to the current I flowing through the coil 107.

On the other hand, when the second movable plate 105 swings, the second torsion spring 103 is twisted, and the relationship between the spring reaction force F ′ of the torsion spring 103 generated thereby and the displacement angle ψ of the second movable plate 105 is ,
ψ = ((F '· L) · l) / (2 · G · I _p ) (1)
Given in. Here, G is the transverse elastic modulus, L is the distance from the central axis of the second torsion spring 103 to the force point, l is the length of the torsion spring portion 103, and _Ip is the secondary secondary pole moment. Then, the second movable plate 105 swings to a position where the generated torque T and F ′ · L are balanced. Therefore, it can be seen that the displacement angle ψ of the second movable plate 105 is proportional to the current I flowing through the coil 107. Therefore, the displacement angle ψ of the second movable plate 105 can be controlled by controlling the current flowing through the coil 107.

  Next, the operation of the first movable plate 104 that swings around the x-axis, that is, the first torsion spring 102 will be described. A magnetic field is formed in a direction crossing the coil 107 by the first permanent magnets 109a and 109b installed so as to sandwich the first torsion spring 102 on both sides of the first movable plate 104. As in the case of the y-axis, when a current is passed from the current source 111 to the coil 107 in the direction of the arrow, a force is generated in the direction in accordance with Fleming's left-hand rule. That is, a vertical force is generated at the end of the first movable plate 104, and the first movable plate 104 swings about the first torsion spring 102. The generated force F is proportional to the product of the magnetic field B formed by the first permanent magnets 109a and 109b and the current I flowing through the coil 107. Therefore, it can be seen that the generated torque T is proportional to the current I flowing through the coil 107. The obtained displacement angle ψ is obtained using Equation (1) as in the case of the y-axis.

  As described above, by passing a current through the coil 107, the second movable plate 105 having the deflection unit 108 can be driven in two axes. As a driving method, the first movable plate 104 and the second movable plate 105 can be held and swung while being tilted by supplying a current to the coil 107 using the current source 111. Further, the first movable plate 104 and the second movable plate 105 are designed to have different torsional resonance frequencies, and are driven by an AC drive having the torsional resonance frequency of the first movable plate 104 or the second movable plate 105. Thus, the displacement angle of one of the axes can be increased. Furthermore, the displacement angle can be increased in both of the two axial directions by driving the first movable plate 104 and the second movable plate 105 with a current in which two resonance frequencies are superimposed. Furthermore, it is also possible to detect the displacement angle of the movable plate 105 using a displacement angle sensor (not shown) and change the current flowing from the current source 111 to control the movement of the movable plate 105.

Next, a manufacturing process will be described with reference to FIG. 3 showing an OB cross section in FIG. However, the dimensions are exaggerated in FIG. 3 to make the process easier to understand.
First, as shown in FIG. 3A, silicon dioxide 115 is formed to a thickness of about 1 μm using a thermal oxidation furnace or the like on a support substrate 106 (thickness: about 500 μm) made of single crystal silicon, and hydrofluoric acid. Patterning is performed using wet etching using a reactive gas or the like, or reactive ion etching using a fluorine-based gas.

Next, as shown in FIG. 3B, after depositing about 50 mm of titanium on the surface silicon dioxide 115 as the electroplating seed electrode 112, about 1000 mm of gold, copper, etc. is deposited by vapor deposition, sputtering, or the like. To do. On top of this, a photoresist 113 is formed to a thickness of about 60 μm and then patterned to form a plating mask. Here, SU-8 (MICROCHEM, which is a photoresist suitable for thick film, is used as photoresist 113.
CORP.) Was used.

  Next, as shown in FIG. 3C, electrolytic copper plating or electroless copper plating is performed to form a copper film with a thickness of about 50 .mu.m. Then, as shown in FIG. 3D, the photoresist 113 is removed using heated N-methylpyrrolidone. Further, the seed electrode 112 is removed using reactive ion etching or ion milling.

Next, as shown in FIG. 3E, a photoresist 114 is formed on the back surface to a thickness of about 3 μm and then patterned. Here, AZ which is a photoresist suitable for the film thickness as the photoresist 114
P4620 (manufactured by Hoechst) was used.

  Next, as shown in FIG. 3F, the support substrate 106 is etched from the back surface by the inductively coupled plasma reactive ion etching to about 200 μm by using the photoresist 114 as an etching mask to a desired thickness. Then, the photoresist 114 is removed.

  Next, as shown in FIG. 3G, etching is performed from the back surface by inductively coupled plasma reactive ion etching using the silicon dioxide 115 as an etching mask until it penetrates the support substrate 106.

  Next, as shown in FIG. 3H, the silicon dioxide 115 is removed from the back surface by wet etching or reactive ion etching using hydrofluoric acid or the like. Further, the deflection unit 108, the first permanent magnets 109a and 109b (not shown), and the second permanent magnet 110 are formed by means of plating, sputtering, or the like. These permanent magnets are also formed by a method of adhering a permanent magnet of a desired size or a method of applying and solidifying a mixture of a rare earth magnet powder in a paste-like adhesive.

[Example 2]
Next, a second embodiment of the present invention will be described. 4 and 5 are diagrams for explaining an optical deflector according to the second embodiment of the present invention. 4 shows a top view, FIG. 5 (a) shows an AA ′ sectional view in FIG. 4, and FIG. 5 (b) shows a BB ′ sectional view in FIG. The basic configuration, driving method, and manufacturing method are almost the same as those of the first embodiment. 4 and 5, 201 is an optical deflector, 202 is a first torsion spring, 203 is a second torsion spring, 204 is a first movable plate, 205 is a second movable plate, 206 is a support substrate, and 207a is a first plate. The coil, 207b is a second coil, 208 is a deflection unit, 209a and 209b are first permanent magnets, 210 is a second permanent magnet, 211a and 211b are current sources, 212 is a lid, and 213 is a support base. In FIG. 4, the first permanent magnet 209a and the lid 212 are not drawn for easy understanding of the structure.

  The second embodiment is characterized in that the first permanent magnets 209a and 209b are respectively installed so as to sandwich the second coil 207b on the first movable plate 204 from the vertical direction, and the opposing magnetic poles are different. Further, the first movable plate 204 has an opening 204a to avoid mechanical interference between the first movable plate 204 and the first permanent magnets 209a and 209b. The first coil 207a is electrically connected to the current source 211a, and the second coil 207b is electrically connected to the current source 211b. The lid 212 is provided with an opening (not shown) and functions as a beam optical path.

  The driving principle around the y axis, that is, the center of the second torsion spring 203 is the same as in the case of the y axis around the first embodiment. The driving principle around the x-axis, that is, the center of the first torsion spring 202 is basically the same as that of the first embodiment regarding the x-axis, although the arrangement of the first permanent magnets 209a and 209b is slightly different. That is, by arranging the first permanent magnets 209a and 209b as shown in FIGS. 4 and 5, the torque at the center of the first torsion spring 202 can be obtained in the first movable plate 204. As for the first permanent magnet, U-shaped permanent magnets 209a and 209b in which the first permanent magnets 209a and 209b in FIG. 5B are integrated may be arranged as shown in FIG. 5C. With this configuration, the magnetic flux density generated in the magnetic pole can be made larger than that in FIG.

  By using the current sources 211a and 211b to pass currents through the first coil 207a and the second coil 207b, the second movable plate 205 having the deflection unit 208 can be swung about two axes. The first coil 207a and the second coil 207b may be electrically connected in series, and in that case, one of the current sources 211a and 211b becomes unnecessary.

  The optical deflector of the present embodiment configured as described above can deflect a light beam biaxially with a simple configuration by arranging permanent magnets and coils as shown in FIGS. It becomes. In addition, since the movable plate and the permanent magnet are devised so as not to interfere mechanically, the displacement angle of the movable plate can be increased.

[Example 3]
6 and 7 are diagrams for explaining an optical deflector according to a third embodiment of the present invention. 6A is a top view, FIG. 6B is an AA ′ sectional view in FIG. 6A, and FIG. 7A is a BB ′ sectional view in FIG. 6A. Show. The basic configuration, driving method, and manufacturing method are almost the same as those of the first embodiment. 6 and 7, 301 is an optical deflector, 302 is a first torsion spring, 303 is a second torsion spring, 304 is a first movable plate, 305 is a second movable plate, 306 is a support substrate, and 307a is a first substrate. Coil, 307b is the second coil, 307c is the third coil, 308 is the deflecting unit, 309a and 309b are the second permanent magnet, 310 is the first permanent magnet, 314a and 314b are the third permanent magnet, 311a, 311b and 311c are A current source, 312 indicates a lid, and 313 indicates a support base. In FIG. 6A, the second permanent magnet 309a, the third permanent magnet 314a, and the lid 312 are not drawn for easy understanding of the structure.

  The third embodiment is characterized in that a plurality of permanent magnets (second permanent magnets 309a and 309b, third permanent magnets 314a and 314b) are provided for driving the first movable plate 304. The second permanent magnets 309a and 309b and the third permanent magnets 314a and 314b are respectively installed so that the second coil 307b and the third coil 307c on the first movable plate 304 are sandwiched from the vertical direction. Are different. In addition, the first movable plate 304 has an opening to avoid mechanical interference with the second permanent magnets 309a and 309b and the third permanent magnets 314a and 314b. The first coil 307a is electrically connected to the current source 311a, the second coil 307b is electrically connected to the current source 311b, and the third coil 307c is electrically connected to the current source 311c. The lid 312 is provided with an opening (not shown) and functions as an optical path of the light beam.

  The driving principle around the y-axis, that is, the center of the second torsion spring 303 is the same as in the case of the y-axis around the second embodiment. The driving principle around the x-axis, that is, the center of the first torsion spring 302 is basically the same as in the case of the x-axis around the second embodiment. That is, by arranging the second permanent magnets 309a and 309b and the third permanent magnets 314a and 314b as shown in FIGS. 6 and 7, the torque at the center of the first torsion spring 302 can be obtained in the first movable plate 304. . As for the second and third permanent magnets, a U-shaped permanent magnet in which the second permanent magnets 309a and 309b and the third permanent magnets 314a and 314b in FIG. 7A are integrated is shown in FIG. 7B. You may arrange as follows.

  Using the current sources 311a, 311b, and 311c, the current is passed through the first coil 307a, the second coil 307b, and the third coil 307c, thereby swinging the second movable plate 305 having the deflection unit 308 about two axes. be able to. Any two or more of the first coil 307a, the second coil 307b, and the third coil 307c may be electrically connected in series. In that case, any one or more of the current sources 311a, 311b, and 311c may be used. Is no longer necessary.

  The optical deflector of this embodiment configured as described above can deflect a light beam in two axes with a simple configuration by arranging permanent magnets and coils as shown in FIGS. Become. Moreover, since the movable plate and the permanent magnet do not interfere mechanically, it is possible to increase the displacement angle of the movable plate. Compared with the second embodiment, the installation area is large, but since a plurality of sets of permanent magnets and coils are provided around one axis, the generated force can be increased and the deflection angle can be increased.

[Example 4]
FIG. 8 is a schematic diagram showing a basic configuration of an image display apparatus according to the present invention which is an optical apparatus using the optical deflector of the present invention. In FIG. 8, reference numeral 501 denotes the optical deflector shown in the above embodiment. In this embodiment, the optical deflector 501 functions as an optical scanner device that raster scans incident light in the horizontal and vertical directions. Reference numeral 502 denotes a laser light source, reference numeral 503 denotes a lens or a lens group, reference numeral 504 denotes a writing lens or lens group, and reference numeral 505 denotes a projection surface (image display surface). An optical deflector 501 is disposed between the two lenses or lens groups 503 and 504.

  Here, the laser light incident from the laser light source 502 is subjected to predetermined intensity modulation related to the timing of optical scanning, and is scanned two-dimensionally by the optical deflector 501 so that it is projected onto the projection surface 505. Form an image.

[Example 5]
FIG. 9 is a schematic diagram showing a basic configuration of an image forming apparatus according to the present invention which is an optical instrument using the optical deflector of the present invention. In FIG. 9, reference numeral 601 denotes an optical deflector configured by providing optical elements such as a mirror, a lens, and a diffraction grating on the mover in the optical deflector shown in the above embodiment. It acts as an optical scanner device that scans in two dimensions. 602 is a laser light source, 603 is a lens or a lens group, 604 is a writing lens or lens group, and 606 is a drum-shaped photoconductor (image display surface). An optical deflector 601 is disposed between the two lenses or lens groups 603 and 604.

  Here, the laser light incident from the laser light source 602 is subjected to predetermined intensity modulation related to the timing of optical scanning, and is scanned two-dimensionally by the optical deflector 601. The scanned laser beam forms an image on the photosensitive member 606 by the writing lens 604. On the other hand, the surface of the photoconductor 606 is uniformly charged by a charger (not shown). Therefore, light is incident on the surface of the photoconductor 606 in a pattern based on scanning by the optical deflector 601, and an electrostatic latent image is formed by the light incident portion and the light non-incident portion. A toner image having a pattern corresponding to the electrostatic latent image on the surface of the photosensitive member 606 is formed by a developing device (not shown), and a visible image is formed by transferring and fixing the toner image on, for example, a paper (not shown).

1A and 1B are diagrams for explaining a first embodiment of an optical deflector according to the present invention, in which FIG. 1A is a top view and FIG. 1B is a cross-sectional view taken along line A-A ′ of FIG. 2A and 2B are diagrams for explaining a first embodiment of the optical deflector according to the present invention. FIG. 2A is a cross-sectional view taken along the line B-B ′ in FIG. 1A, and FIG. FIG. 3 is a cross-sectional view illustrating a manufacturing process of Example 1 of the present invention. FIG. 4 is a top view for explaining a second embodiment of the optical deflector according to the present invention. 5A and 5B are diagrams for explaining an optical deflector according to a second embodiment of the present invention. FIG. 5A is a cross-sectional view taken along the line AA 'in FIG. 4, and FIG. 5B is a cross-sectional view taken along the line BB' in FIG. (C) is a BB ′ cross-sectional view showing a modification. 6A and 6B are diagrams for explaining an optical deflector according to a third embodiment of the present invention, in which FIG. 6A is a top view and FIG. 6B is a cross-sectional view taken along line A-A ′ of FIG. 7A and 7B are views for explaining a third embodiment of the optical deflector according to the present invention. FIG. 7A is a sectional view taken along line BB ′ in FIG. 6A, and FIG. 'Cross section. FIG. 8 is a schematic view for explaining an embodiment of the image display apparatus of the present invention. FIG. 9 is a schematic view for explaining an embodiment of the image forming apparatus of the present invention. FIG. 10 is a top view for explaining the first prior art. FIG. 11 is a top view for explaining the second prior art. FIG. 12 is a top view for explaining the third prior art.

Explanation of symbols

101, 201, 301: Optical deflector
102, 202, 302: First torsion spring
103, 203, 303: Second torsion spring
104, 204, 304: First movable plate
105, 205, 305: Second movable plate
106, 206, 306: Support substrate
107: Coil
108, 208, 308: Deflection section
109a, 109b, 209a, 209b, 310: First permanent magnet
110, 210, 309a, 309b: second permanent magnet
111, 211a, 211b, 311a, 311b, 311c: current source
113, 114: Photoresist
115: Silicon dioxide
204a: Opening
207a, 307a: First coil
207b, 307b: second coil
212, 312: Lid
213, 313: Support stand
307c: Third coil
314a, 314b: Third permanent magnet
501, 601: Optical deflector
502, 602: Laser light source
503, 603: Lens or lens group
504, 604: Writing lens or lens group
505: Projection plane
606: Photoconductor

Claims (9)

A first movable plate that swings about a first rotation axis, a first elastic support portion that supports the first movable plate in a swingable manner, and a support that fixes the first elastic support portion A substrate, first magnetic field generating means disposed at a position spaced from the first movable plate, a second movable plate swinging about a second rotation axis, and the second movable plate. A swinging device including a second elastic support portion that is swingably supported and fixed to the first movable plate,
A first coil is provided on the first movable plate so as to circulate around the second movable plate; a second magnetic field generating means is provided on the second movable plate;
A second coil is further installed on the first movable plate, the first movable plate has a first opening in the inner periphery of the second coil, and N of the first magnetic field generating means poles and is the S pole, the first movable plate said first spaced locations to the first aspect and to that rocking device to be placed across the opening from the movable plate in a direction substantially perpendicular to the . 2. The oscillating device according to claim 1, wherein the first elastic support portions are a pair of elastic support members disposed on the same axis and disposed on both sides of the first movable plate. . 2. The oscillating device according to claim 1, wherein the second elastic support portion is a pair of elastic support members disposed on the same axis and disposed on both sides of the second movable plate. . The swing device according to claim 1, wherein the first coil circulates around the second movable plate in a square shape. The second coil and the third coil are further installed on the first movable plate with the first rotating shaft interposed therebetween, and the first movable plate is further provided on the inner periphery of the third coil. The second opening is provided, and the N pole and the S pole of the third magnetic field generating means are further separated from the first movable plate in a direction substantially perpendicular to the first movable plate. The swinging device according to claim 1 , wherein the swinging device is disposed with the opening of the first and second openings interposed therebetween. A current including a frequency component of a torsional resonance frequency of the second movable plate is applied to the first coil, and a torsional resonance frequency component of the first movable plate is applied to the second coil or the third coil. The oscillating device according to claim 5 , wherein a current including is applied. An optical deflector using the oscillating device according to any one of claims 1 to 6, light, wherein a deflecting unit for deflecting the incident light is provided on the second movable plate Deflector. An image display device comprising: a light source; and the light deflector according to claim 7 for deflecting light emitted from the light source. 8. An image forming apparatus comprising: a light source; an optical deflector according to claim 7 that deflects light emitted from the light source; and a photosensitive material onto which the light deflected by the optical deflector is projected. apparatus.